In response to the expanding need for advanced live cell imaging capabilities, the School of Veterinary Medicine established an Imaging Core facility, which came online in the summer of 2008. With the heavy involvement of several pioneer labs, we have implemented a range of cutting edge applications and in less than one year have developed a dedicated and broad user base with 12 NIH funded labs actively generating data from the facility. In addition, 7 labs are in the consultation and experimental design stage, indicating a rapidly expanding interest in utilizing the core facility. Expanding utilization of the core has been greatly facilitated by the expertise of our core director, Dr. Lingli Zhang, who has been instrumental in developing and implementing a range of new applications for our user. As a group we have developed an enormous amount of collective expertise, including real-time imaging of pathogen infection and immune responses in the brain, intestine, skin, and secondary lymphoid organs, FRET based approaches to track the localization, interactions, and activity of signaling molecules in response to receptor stimulation, photo-activation to generate signaling intermediates instantaneously in situ, and live imaging of calcium and mitochondrial function. Although the core has been fully operational for a relatively short time, data generated have contributed to an Immunity paper, and results of other studies have been submitted for publication or are in final stages of preparation. The experimental needs of our user group continuously drives us to expand our capability and each of the hardware components requested in this proposal was chosen to address specific current needs, and also to anticipate future needs, with the ultimate goal of improving our 2 photon/spectral imaging capability. Funds requested will therefore be used for upgraded hardware that will enhance the capability of our core confocal/2 photon spectral imaging system in 3 general ways;1) increase the temporal resolution, spatial coverage, and detection sensitivity of the microscope, 2) provide capability for drug application and adequate environmental control for long term real time imaging of living tissues and cells, and 3) expand the overall capability of the instrument to perform Forster resonance energy transfer (FRET) and fluorescence lifetime imaging.